Arrangement in a rock drilling equipment

ABSTRACT

An arrangement for controlling the oscillation of a rock drilling equipment, comprising oscillation cylinders acting between a body and two crawlers, an oscillation selector valve allowing the oscillation cylinders to be interconnected. Locking valves are mounted in the oscillation cylinders, which valves prevent the flow of pressure fluid from the oscillation cylinders e.g., in the case of a hose damage, thus locking the crawlers and the body against movement relative to each other.

TECHNICAL FIELD

The invention relates to an arrangement in a rock drilling equipment forcontrolling oscillation, comprising oscillation cylinders acting betweena body and two crawlers, respectively, an oscillation selector valveallowing the oscillation cylinders to be interconnected during the driveof the equipment so that when one cylinder is extended the othercylinder is contracted, and vice versa.

BACKGROUND

In a crawler-base rock drilling equipment, each crawler is connected tothe equipment body by an oscillation cylinder positioned between thecrawler frame and the body and a transverse turning axle allowing thecrawler to turn with respect to the equipment in accordance with theirregularities of the underlying surface. In order that the equipmentwould move more evenly in the terrain and would load the body to alesser extent, the oscillation cylinders are interconnected duringnormal drive in such a way that when the other crawler turns in onedirection with respect to the equipment, the other crawler has to turncorrespondingly in the opposite direction, and so the equipment willstay in balance. A drawback of the prior art is, however, that thecylinders have to be interconnected by hoses in order that the equipmentcould operate, the cylinders could move and the crawlers turn. When ahose is damaged for one reason or another, the pressure escapes from theoscillation cylinders and there is the danger that the equipment mayfall over.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an arrangement bymeans of which the balance of the equipment can be controlled easily andreliably in as many situations as possible. The arrangement according tothe invention is characterized in that it comprises locking valvesmounted in the oscillation cylinders, said valves being connected tohydraulic lines for the oscillation cylinders such that the flow ofpressure fluid out of the oscillation cylinders through the hydrauliclines is normally blocked, and that the locking valves comprise guidemeans, which release the flow of pressure fluid in the hydraulic linesof the cylinders by a pressure applied to the locking valves. Anessential feature of the invention is that the locking valves aremounted in the oscillation cylinders, and connected to the hydrauliclines of the oscillation cylinders such that the hydraulic lines arenormally closed, whereby the oscillation cylinders are fixed in theposition in which they are. Another essential feature of the inventionis that the locking valves are controllable by an external separatepressure, so that they can be e.g. opened automatically while drivingthe equipment onwards by taking the control pressure from a line whichis pressurized during drive. Still another essential feature of theinvention is that, if required, the oscillation may be locked out e.g.when the drilling boom or the upper carriage of the equipment turnsoutwards from the longitudinal direction of the equipment through apredetermined angle. In this way, the risk of falling caused by changesin balance can be avoided.

An advantage of the arrangement according to the invention is that whenthe hoses between the oscillation cylinders are damaged, the controlpressure of the valve may be guided directly into the tank, forinstance, and the valves are closed, fixing the cylinders in position sothat the crawlers will be locked stationary with respect to the body ofthe equipment. Further, the equipment is constantly safe as theoscillation is opened only during drive and it need not always be paidattention to separately. Moreover, the invention provides extra safetyin that the oscillation can be easily locked out in unusual conditions,and the locking out can be automated by utilizing sensors connected tothe turning mechanism of the boom or the upper carriage.

The invention will be described more fully with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a rock drilling equipment in apartial section;

FIGS. 2a to 2c illustrate schematically the oscillation of the rockdrilling equipment;

FIG. 3 illustrates schematically an arrangement according to theinvention for connecting oscillation cylinders;

FIGS. 4a and 4b show one embodiment for switching off oscillation basedon the turning angle of the boom or the upper carriage; and

FIG. 5 is a schematic view of another embodiment of the arrangementaccording to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a rock drilling equipment comprising crawlers 1 and 2connected pivotally about an axis 3 with respect to a body 4. The body 4comprises all required power means, control means, etc., which as suchare well-known, and therefore they and their operation will not bedescribed more closely. An oscillation cylinder 5 and 6 is providedbetween frames 1a and 2a for each crawler, respectively, and the body 4.The oscillation cylinders act between the body and the crawlers so thatthe body will not tilt over about the axis 3. A boom 7 is furtherattached to the body, and a feeding beam 8 is attached to the end of theboom. The structures and operations of the boom and the feeding beam arewell-known and less relevant to the invention, wherefore their operationwill not be described more closely herein. The equipment shown in FIG. 1further comprises a cabin 9 connected to the frame of the crawler 1 suchthat it moves together with the crawler when the crawler pivots aboutthe axis 3. Generally speaking, this kind of cabin is not necessary andit is not essential to the invention. As a matter of fact, the inventionmay be applied in all kind of equipment comprising two crawlerssimilarly pivotable about a horizontal axis apart from each other. Inthe figures to be described below, no components unessential to theinvention, such as the boom 7, the feeding beam 8, and the cabin 9, havebeen shown for the sake of clarity unless it is necessary for theunderstanding of the invention.

FIGS. 2a to 2c illustrate schematically the principle of the oscillationoperation. In all of the figures, the body 4 is shown only partially ina substantially horizontal position, and the crawlers 1 and 2 are shownin different positions according to the situation. In FIG. 2a, thecrawler 1 is in a downwardly turned position due to the terrainconditions, whereby the crawler 2 is correspondingly in an upwardlyturned position. In FIG. 2b, both of the crawlers are on a substantiallyeven surface, and are thus parallel to each other. In FIG. 2c, in turn,the situation is the opposite of that of FIG. 2a, whereby the crawler 1is on a rising surface and the crawler 2 is correspondingly on a fallingsurface.

FIG. 3 shows schematically an arrangement, where the oscillationhydraulics of the drilling equipment is connected so as to achieve theoperation according to the invention. The figure showspressure-controlled non-return valves i.e. locking valves 10a, 10b and11a, 11b mounted in connection with the oscillation cylinders 5 and 6.Hydraulic lines to the cylinder spaces of the cylinders 5 and 6 passthrough the locking valves. Pressure fluid connections between thelocking valve 10a, 10b and 11a, 11b and the oscillation cylinders 5 and6, respectively, are realized as fixed, rigid pipes or as fixed lines inorder to prevent hose damage between them. The operation of the lockingvalves 10a, 10b and 11a, 11b is based on the fact that they are openablefor operation merely by an external pressure through control lines 12and 13. Accordingly, if no pressure is supplied to the control lines,the locking valves 10a, 10b and 11a, 11b remain closed, and thecylinders 5 and 6 remain locked in the positions where they were whenthe locking valves were closed the preceding time. Hydraulic lines 14and 15 are provided between the oscillation cylinders 5 and 6. There arepressure hoses in order that the crawlers 1 and 2 and the oscillationcylinders 5 and 6 could move with respect to the body. The hydrauliclines 14 and 15 between the cylinders 5 and 6 are connected so that whenthe length of one cylinder decreases, the length of the other cylinderincreases, and vice versa, when an oscillation selector valve 16 is in aposition shown in the figure, and control pressure is applied to thelocking valves 10a, 10b and 11a, 11b through the control lines 12 and13. In another embodiment, the control lines 12 and 13 are furtherprovided with control valves 17, 18, through which control pressure canbe applied from a control pressure line 19 to the locking valves 10a,10b and 11a, 11b. The arrangement further comprises a pressure gauge 21connected to both of the hydraulic lines 14 and 15 of the oscillationcylinders via a shuttle valve 20. The pressure gauge 21 senses pressureprevailing in the lines 14 and 15. In practice, the lines 14 and 15 arehoses which may be damaged when the equipment is used. Thus, when thehose is damaged, the hydraulic pressure prevailing in the line formed byit drops, and the pressure gauge 21 detects the pressure drop. Thepressure gauge 21 in turn is most advantageously connected electricallyto control the control valves 17 and 18, which are forced downwards inthe figure, if the hose is damaged, so that the pressure of the controllines 12 and 13 is discharged into a tank for pressure fluid, and so thelocking valves 10a, 10b and 11a, 11b are displaced to a closed position,thus locking the oscillation cylinders 5 and 6 in their currentposition. As a result of this, the equipment will not fall over in spiteof the hose damage.

FIG. 3 shows the oscillation selector valve 16 in a free oscillationposition, whereby the rest of the hydraulics is separated from theoscillation cylinders. If the body 4 is to be slanted with respect tothe crawlers 1 and 2 in some direction, e.g. when the body 4 should bepositioned horizontally during drilling to facilitate the drillingmathematics and the control of the drilling process, the oscillationselector valve can be displaced from the position shown in the figure ineither direction, so that both of the oscillation cylinders arecontracted or extended in the same direction. If required, it is alsopossible to displace one crawler independently of the other e.g. bymeans of separate cylinder-specific electric switches positioned betweenthe pressure gauge 21 and the valves 17 and 18. Furthermore, a shuttlevalve 25 connected to hydraulic lines 23 and 24 for a drive controlvalve 22 of drive motors not shown in the figures is connected to thecontrol pressure line 19 of the control valves 17 and 18. A hydraulicline from the shuttle valve 25 in turn is connected to the controlpressure line 19 of the control valves 17 and 18 by another shuttlevalve 26, to the other side of which a control pressure line 27 from theoscillation selector valve is connected. As a consequence, controlpressure acting in either direction is able to guide the locking valveto the open position to allow operation. In this way the body 4 can beadjusted with respect to the crawlers by the use of the oscillationselector valve, whereby the locking valves 10a, 10b and 11a, 11b openwhen the oscillation selector valve is operated by a pressure applied toeither one of the lines. Correspondingly, when the equipment is drivenonwards, the pressure prevailing in either one of the lines 23 or 24 tothe drive motor opens the locking valves 10a, 10b and 11a, 11b, and sooscillation is possible during drive. It is further possible to connecta separate regulating valve 28 to the control pressure line 19, and theoscillation can be switched off permanently by the use of the regulatingvalve in certain conditions, or by electrically controlling the valves17 and 18 directly. The figure further shows schematically a pump 29 forpressure fluid, by means of which pressure fluid is introduced into theentire hydraulic system. This, however, is a prior art technique, whichwill not be described more fully herein.

FIGS. 4a to 4b show an embodiment where guide projections 31 and 32 aremounted to the shaft of the boom, or in an arrangement where the uppercarriage of the drilling equipment is pivotable, to its vertical shaft30, and a closing valve 33 is provided beside the shaft 30, a tip 34 ofthe spindle of the closing valve being arranged to be guided by thecontrol projections 31 and 32. When the shaft turns through an anglewider than an angle a indicated in the figure, as shown in FIG. 4b, theguide projection 31, or 32 in the case of the figure, pushes the spindleof the closing valve 33 inwards, whereby it stops the supply of pressurefluid into the control pressure line 19, and the locking valves 10a, 10band 11a, 11b are closed, thus preventing the oscillation and the fallingof the equipment when the balance changes. Sensing the turning anglebased on mechanical operation and closing the valve may also be realizedby various limit switches or inductively or in another way of sensingknown per se by the use of an electric or hydraulic control. The closingvalve 33 may replace the regulating valve 28 shown in FIG. 3 or bepositioned in series with it so that the turning of the boom or theupper carriage about its vertical shaft 30 always locks the oscillationcylinders irrespective of the position of the regulating valve.Alternatively, an electric sensor may control the valves 17 and 18directly.

FIG. 5 shows schematically an embodiment of the invention, whereby thesame reference numerals as in FIG. 3 have been used for the samecomponents. The figure shows the same components as in FIG. 3 exceptthat it further shows additional pressure limit switches 35 and 36,which are not always necessary and which protect the oscillationcylinders 5 and 6 and the locking valves 10a, 10b and 11a, 11b fromexcessive pressure peaks e.g. when the crawler of the drilling equipmentsuddenly drops due to a threshold or a hole or the like when theequipment is in motion. In the figure the pressure limit switchingarrangement 35, 36 is made only to one of the hydraulic lines, but it isalso possible to switch such an arrangement to both hydraulic lines. Thefigure also shows shuttle valve 37a, 37b and 38a, 38b, the purpose ofwhich is to allow the opening of the locking valves 10a, 10b and 11a,11b when pressure fluid is applied to either one or both of thecylinders so as to adjust the position of the body of the equipment e.gto a horizontal position in a slanting drilling site. These valves allowthe pressure entering one of the hydraulic lines to open also thelocking valve of the opposite line, thus allowing the flow of fluid outof the cylinder. The figure further shows a throttle 39, which allowsthe discharge of the control pressure into the tank when controlpressure is relieved from the pressure line 19, thus also allowing thelocking valves 10a, 10b and 11a, 11b to close. In this embodiment thelocking valves 10a, 10b and 11a, 11b, the shuttle valves 37a, 37b, andthe throttle 39 form an integral whole, i.e. a valve block 41.Similarly, the corresponding components for the other oscillationcylinder 6 form a valve block 42. The entity will thus be extremelyoperative, and this type of valve block may be mounted to the side ofthe oscillation cylinder or be integral with it. Essential is that theoscillation cylinder and the associated valve block or associated valveshave no damageable hose for pressure fluid, but all lines are fixed orfixedly mounted rigid pipes protected in the best possible way. Thefigure further shows shuttle valves 43, which close the hydraulic linesto the oscillation selector valve 16 when no pressure fluid is beingsupplied to the cylinders. The pressure fluid is thus not able to escapefrom the circuit of the oscillation cylinders 5 and 6, but the circuitremains closed. The structure and operation of the shuttle valves 43 arewell-known and obvious to one skilled in the art, and therefore will notbe described more closely.

The invention has been described above and shown in the drawings only byway of example and it is in no way limited to the examples. The lockingvalves may be mounted either fixedly to the oscillation cylinders or tothe side of the cylinders as separate valves or, as shown in FIG. 5, asvalve blocks. Control pressure for the locking valves may be takenautomatically from an operative hydraulic line of the drive motor orfrom some other pressure source if separate oscillation is needed forsome reason. Similarly, control pressure for the closing valves may beswitched off for various reasons, e.g. when the boom or the uppercarriage turns excessively from the point of view of safety.

We claim:
 1. In rock drilling equipment which includes a pair ofcrawlers and a body, an arrangement for controlling oscillation of saidequipment in a manner sufficient to prevent tipping over of saidequipment, the arrangement comprising oscillation cylinders actingbetween the body and said pair of crawlers, respectively; an oscillationselector valve allowing said oscillation cylinders to be interconnectedduring driving of the equipment so that when one of said cylinders isextended, the other of said cylinders is contracted, and vice versa;locking valves mounted in said oscillation cylinders, said lockingvalves being connected to hydraulic lines for said oscillation cylinderssuch that flow of pressure fluid out of said oscillation cylindersthrough the hydraulic lines is normally blocked, and wherein saidlocking valves each include a separate control line for applying controlpressure to said locking valves to release the flow of pressure fluid inthe hydraulic lines of said oscillation cylinders.
 2. In rock drillingequipment which includes a pair of crawlers and a body, an arrangementfor controlling oscillation of said equipment in a manner sufficient toprevent tipping over of said equipment, the arrangement comprisingoscillation cylinders acting between the body and said pair of crawlers,respectively; an oscillation selector valve allowing said oscillationcylinders to be interconnected during driving of the equipment so thatwhen one of said cylinders is extended, the other of said cylinders iscontracted, and vice versa; locking valves mounted in said oscillationcylinders, said locking valves being connected to hydraulic lines forsaid oscillation cylinders such that flow of pressure fluid out of saidoscillation cylinders through the hydraulic lines is normally blocked,and wherein said locking valves each include a separate control line forapplying control pressure to said locking valves to release the flow ofpressure fluid in the hydraulic lines of said oscillation cylinders,wherein said locking valves further include shuttle valves mountedbetween said separate control lines and said hydraulic lines betweensaid oscillation cylinders, which shuttle valves are connected such thatpressure prevailing in one of said hydraulic lines and said separatecontrol lines is able to open said locking valves.
 3. The arrangementaccording to claim 2, characterized in further comprising a throttlecommunicating with another control pressure line of said oscillationcylinders and a pressure fluid tank, whereby when pressure in saidanother control pressure line is relieved, control pressure of saidlocking valves is able to escape through said throttle, and the lockingvalves are closed.
 4. The arrangement according to claim 2, wherein saidshuttle valves and respective locking valves are connected together intoan integral valve block.
 5. In rock drilling equipment which includes apair of crawlers and a body, an arrangement for controlling oscillation,comprising oscillation cylinders acting between the body and said pairof crawlers, respectively; an oscillation selector valve allowing saidoscillation cylinders to be interconnected during driving of theequipment so that when one of said cylinders is extended, the other ofsaid cylinders is contracted, and vice versa; locking valves mounted insaid oscillation cylinders, said locking valves being connected tohydraulic lines for said oscillation cylinders such that flow ofpressure fluid out of said oscillation cylinders through the hydrauliclines is normally blocked, and wherein said locking valves each includea separate control line for applying control pressure to said lockingvalves to release the flow of pressure fluid in the hydraulic lines ofsaid oscillation cylinders, and further comprising a pressure gaugearranged to sense pressure in each one of said hydraulic lines betweensaid oscillation cylinders; and further wherein another control pressureline to said locking valves is provided with at least one control valvearranged to close said another control pressure line under guidance ofsaid pressure gauge in such a way that said locking valves close saidhydraulic lines.
 6. The arrangement according to claim 5, wherein eachof said control lines of said locking valves for said oscillationcylinders has its own control valve and further wherein said lockingvalves and respective control valves are connected together into anintegral valve block in connection with respective ones of saidoscillation cylinders.
 7. The arrangement according to claim 5, whereinsaid pressure gauge is arranged to control said control valveselectrically.
 8. In rock drilling equipment which includes a pair ofcrawlers and a body, an arrangement for controlling oscillation,comprising oscillation cylinders acting between the body and said pairof crawlers, respectively; an oscillation selector valve allowing saidoscillation cylinders to be interconnected during driving of theequipment so that when one of said cylinders is extended, the other ofsaid cylinders is contracted, and vice versa; locking valves mounted insaid oscillation cylinders, said locking valves being connected tohydraulic lines for said oscillation cylinders such that flow ofpressure fluid out of said oscillation cylinders through the hydrauliclines is normally blocked, and wherein said locking valves each includea separate control line for applying control pressure to said lockingvalves to release the flow of pressure fluid in the hydraulic lines ofsaid oscillation cylinders, and further comprising pressure limitswitches connected between cylinder spaces in said oscillation cylindersand said hydraulic lines between said oscillation cylinders such thatpressure peaks exceeding a predetermined level allow flow of pressurefluid from cylinder spaces into said hydraulic lines.
 9. The arrangementaccording to claim 8, wherein said locking valves are connected to saidcylinder spaces of said oscillation cylinders by rigid pipes or fixedlines.